You should not get any errors or warnings and see a list of dockers running on your host. If you get error for docker-py then you can install the same with :

pip install docker-py

And now is the good time to open the docker.py script to check the documentation. It adds all the docker hosts as entry in itself. But cool thing I liked is the fact that it creates a group for all running dockers – which is very very useful.

Now, if I want to set the Timezone (TZ) on all the running dockers in one go, I can do this:

And just in case, the above does not work for you and you have a common username/password on all the machines, then another thing you would love is following:

# Export the docker host. If that is localhost, then you do not need this.
export DOCKER_HOST=tcp://192.168.122.1:4243
# This is GOOD to set option. This is the default IP address for docker
# and setting this to first IP address of the docker network is good idea
# that would ensure that ansible can login to each docker.
# And note - you need to have ssh running on all the dockers for the commands to work
export DOCKER_DEFAULT_IP=192.168.122.1
ansible -i docker.py -m setup -u root -a 'filter=ansible_eth[0-2]' all